Calculating Heat Loss from Room with Refrigerator and Heater

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Discussion Overview

The discussion revolves around calculating the heat loss from a room that contains a refrigerator and a heater, focusing on the conditions under which the air temperature remains constant despite the operation of both appliances. The scope includes conceptual reasoning and mathematical calculations related to energy conservation.

Discussion Character

  • Exploratory, Technical explanation, Homework-related

Main Points Raised

  • James presents a scenario involving a room with specific air properties and appliances, seeking help to calculate heat loss.
  • Another participant suggests that the problem contains a trick, implying that the solution may be simpler than it appears.
  • James proposes a calculation based solely on the refrigerator's data, suggesting a heat loss of 1250 kW, and seeks confirmation on this approach.
  • A later reply emphasizes the principle of conservation of energy, indicating that at equilibrium, the heat inputs and outputs must balance.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the correct calculation method or the interpretation of the problem, with multiple viewpoints and interpretations presented.

Contextual Notes

There are assumptions regarding the conditions of equilibrium and the definitions of heat loss that are not fully explored, which may affect the calculations.

oliverjames
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A room contains 25 kg of air at 100KPa and 10 degree C. The room has a 250-W refrigerator (the refrigerator consumes 250 W of electricity when running) and 1-KW electric resistance heater. During a cold winter day, it is observed that both the refrigerator and the resistance heater are running continuously but the air temperature in the room remains constant. The rate of heat loss from the room during that day is:

I`m having trouble solving this . can anyone please help?

cheers
james
 
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It's a bit of a trick question, but when you see the trick, it is rediculously easy (that should be a hint...).
 
ok . if i omit the room criteria and if i`m taking only the refrigerator data the heat loss to the room would be 1250 Kw. correct me if i was wrong. Thanks . James
 
Yep, it really is that easy. Nice! Conservation of energy says that if you're at an equilibrium, the inputs and outputs must be equal.
 

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